// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}


/*
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DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

  17. Interpretation of Sections 15 and 16.

  If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.

                     END OF TERMS AND CONDITIONS

            How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:

    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".

  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/

# @version 0.2.12
# (c) Curve.Fi, 2021
# Pool for USDT/BTC/ETH or similar

interface ERC20:  # Custom ERC20 which works for USDT, WETH and WBTC
    def transfer(_to: address, _amount: uint256): nonpayable
    def transferFrom(_from: address, _to: address, _amount: uint256): nonpayable
    def balanceOf(_user: address) -> uint256: view

interface CurveToken:
    def totalSupply() -> uint256: view
    def mint(_to: address, _value: uint256) -> bool: nonpayable
    def mint_relative(_to: address, frac: uint256) -> uint256: nonpayable
    def burnFrom(_to: address, _value: uint256) -> bool: nonpayable


interface Math:
    def geometric_mean(unsorted_x: uint256[N_COINS]) -> uint256: view
    def reduction_coefficient(x: uint256[N_COINS], fee_gamma: uint256) -> uint256: view
    def newton_D(ANN: uint256, gamma: uint256, x_unsorted: uint256[N_COINS]) -> uint256: view
    def newton_y(ANN: uint256, gamma: uint256, x: uint256[N_COINS], D: uint256, i: uint256) -> uint256: view
    def halfpow(power: uint256, precision: uint256) -> uint256: view
    def sqrt_int(x: uint256) -> uint256: view


interface Views:
    def get_dy(i: uint256, j: uint256, dx: uint256) -> uint256: view
    def calc_token_amount(amounts: uint256[N_COINS], deposit: bool) -> uint256: view


interface WETH:
    def deposit(): payable
    def withdraw(_amount: uint256): nonpayable


# Events
event TokenExchange:
    buyer: indexed(address)
    sold_id: uint256
    tokens_sold: uint256
    bought_id: uint256
    tokens_bought: uint256

event AddLiquidity:
    provider: indexed(address)
    token_amounts: uint256[N_COINS]
    fee: uint256
    token_supply: uint256

event RemoveLiquidity:
    provider: indexed(address)
    token_amounts: uint256[N_COINS]
    token_supply: uint256

event RemoveLiquidityOne:
    provider: indexed(address)
    token_amount: uint256
    coin_index: uint256
    coin_amount: uint256

event CommitNewAdmin:
    deadline: indexed(uint256)
    admin: indexed(address)

event NewAdmin:
    admin: indexed(address)

event CommitNewParameters:
    deadline: indexed(uint256)
    admin_fee: uint256
    mid_fee: uint256
    out_fee: uint256
    fee_gamma: uint256
    allowed_extra_profit: uint256
    adjustment_step: uint256
    ma_half_time: uint256

event NewParameters:
    admin_fee: uint256
    mid_fee: uint256
    out_fee: uint256
    fee_gamma: uint256
    allowed_extra_profit: uint256
    adjustment_step: uint256
    ma_half_time: uint256

event RampAgamma:
    initial_A: uint256
    future_A: uint256
    initial_gamma: uint256
    future_gamma: uint256
    initial_time: uint256
    future_time: uint256

event StopRampA:
    current_A: uint256
    current_gamma: uint256
    time: uint256

event ClaimAdminFee:
    admin: indexed(address)
    tokens: uint256


N_COINS: constant(int128) = 3  # <- change
PRECISION: constant(uint256) = 10 ** 18  # The precision to convert to
A_MULTIPLIER: constant(uint256) = 10000

# These addresses are replaced by the deployer
math: constant(address) = 0x8F68f4810CcE3194B6cB6F3d50fa58c2c9bDD1d5
token: constant(address) = 0xc4AD29ba4B3c580e6D59105FFf484999997675Ff
views: constant(address) = 0x40745803C2faA8E8402E2Ae935933D07cA8f355c
coins: constant(address[N_COINS]) = [
    0xdAC17F958D2ee523a2206206994597C13D831ec7,
    0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599,
    0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2,
]

price_scale_packed: uint256   # Internal price scale
price_oracle_packed: uint256  # Price target given by MA

last_prices_packed: uint256
last_prices_timestamp: public(uint256)

initial_A_gamma: public(uint256)
future_A_gamma: public(uint256)
initial_A_gamma_time: public(uint256)
future_A_gamma_time: public(uint256)

allowed_extra_profit: public(uint256)  # 2 * 10**12 - recommended value
future_allowed_extra_profit: public(uint256)

fee_gamma: public(uint256)
future_fee_gamma: public(uint256)

adjustment_step: public(uint256)
future_adjustment_step: public(uint256)

ma_half_time: public(uint256)
future_ma_half_time: public(uint256)

mid_fee: public(uint256)
out_fee: public(uint256)
admin_fee: public(uint256)
future_mid_fee: public(uint256)
future_out_fee: public(uint256)
future_admin_fee: public(uint256)

balances: public(uint256[N_COINS])
D: public(uint256)

owner: public(address)
future_owner: public(address)

xcp_profit: public(uint256)
xcp_profit_a: public(uint256)  # Full profit at last claim of admin fees
virtual_price: public(uint256)  # Cached (fast to read) virtual price also used internally
not_adjusted: bool

is_killed: public(bool)
kill_deadline: public(uint256)
transfer_ownership_deadline: public(uint256)
admin_actions_deadline: public(uint256)

admin_fee_receiver: public(address)

KILL_DEADLINE_DT: constant(uint256) = 2 * 30 * 86400
ADMIN_ACTIONS_DELAY: constant(uint256) = 3 * 86400
MIN_RAMP_TIME: constant(uint256) = 86400

MAX_ADMIN_FEE: constant(uint256) = 10 * 10 ** 9
MIN_FEE: constant(uint256) = 5 * 10 ** 5  # 0.5 bps
MAX_FEE: constant(uint256) = 10 * 10 ** 9
MAX_A: constant(uint256) = 10000 * A_MULTIPLIER * N_COINS**N_COINS
MAX_A_CHANGE: constant(uint256) = 10
MIN_GAMMA: constant(uint256) = 10**10
MAX_GAMMA: constant(uint256) = 10**16
NOISE_FEE: constant(uint256) = 10**5  # 0.1 bps

PRICE_SIZE: constant(int128) = 256 / (N_COINS-1)
PRICE_MASK: constant(uint256) = 2**PRICE_SIZE - 1

# This must be changed for different N_COINS
# For example:
# N_COINS = 3 -> 1  (10**18 -> 10**18)
# N_COINS = 4 -> 10**8  (10**18 -> 10**10)
# PRICE_PRECISION_MUL: constant(uint256) = 1
PRECISIONS: constant(uint256[N_COINS]) = [
    1000000000000,
    10000000000,
    1,
]

INF_COINS: constant(uint256) = 15


@external
def __init__(
    owner: address,
    admin_fee_receiver: address,
    A: uint256,
    gamma: uint256,
    mid_fee: uint256,
    out_fee: uint256,
    allowed_extra_profit: uint256,
    fee_gamma: uint256,
    adjustment_step: uint256,
    admin_fee: uint256,
    ma_half_time: uint256,
    initial_prices: uint256[N_COINS-1]
):
    self.owner = owner

    # Pack A and gamma:
    # shifted A + gamma
    A_gamma: uint256 = shift(A, 128)
    A_gamma = bitwise_or(A_gamma, gamma)
    self.initial_A_gamma = A_gamma
    self.future_A_gamma = A_gamma

    self.mid_fee = mid_fee
    self.out_fee = out_fee
    self.allowed_extra_profit = allowed_extra_profit
    self.fee_gamma = fee_gamma
    self.adjustment_step = adjustment_step
    self.admin_fee = admin_fee

    # Packing prices
    packed_prices: uint256 = 0
    for k in range(N_COINS-1):
        packed_prices = shift(packed_prices, PRICE_SIZE)
        p: uint256 = initial_prices[N_COINS-2 - k]  # / PRICE_PRECISION_MUL
        assert p < PRICE_MASK
        packed_prices = bitwise_or(p, packed_prices)

    self.price_scale_packed = packed_prices
    self.price_oracle_packed = packed_prices
    self.last_prices_packed = packed_prices
    self.last_prices_timestamp = block.timestamp
    self.ma_half_time = ma_half_time

    self.xcp_profit_a = 10**18

    self.kill_deadline = block.timestamp + KILL_DEADLINE_DT

    self.admin_fee_receiver = admin_fee_receiver


@payable
@external
def __default__():
    pass


@internal
@view
def _packed_view(k: uint256, p: uint256) -> uint256:
    assert k < N_COINS-1
    return bitwise_and(
        shift(p, -PRICE_SIZE * convert(k, int256)),
        PRICE_MASK
    )  # * PRICE_PRECISION_MUL


@external
@view
def price_oracle(k: uint256) -> uint256:
    return self._packed_view(k, self.price_oracle_packed)


@external
@view
def price_scale(k: uint256) -> uint256:
    return self._packed_view(k, self.price_scale_packed)


@external
@view
def last_prices(k: uint256) -> uint256:
    return self._packed_view(k, self.last_prices_packed)


@external
@view
def token() -> address:
    return token


@external
@view
def coins(i: uint256) -> address:
    _coins: address[N_COINS] = coins
    return _coins[i]


@internal
@view
def xp() -> uint256[N_COINS]:
    result: uint256[N_COINS] = self.balances
    packed_prices: uint256 = self.price_scale_packed

    precisions: uint256[N_COINS] = PRECISIONS

    result[0] *= PRECISIONS[0]
    for i in range(1, N_COINS):
        p: uint256 = bitwise_and(packed_prices, PRICE_MASK) * precisions[i]  # * PRICE_PRECISION_MUL
        result[i] = result[i] * p / PRECISION
        packed_prices = shift(packed_prices, -PRICE_SIZE)

    return result


@view
@internal
def _A_gamma() -> uint256[2]:
    t1: uint256 = self.future_A_gamma_time

    A_gamma_1: uint256 = self.future_A_gamma
    gamma1: uint256 = bitwise_and(A_gamma_1, 2**128-1)
    A1: uint256 = shift(A_gamma_1, -128)

    if block.timestamp < t1:
        # handle ramping up and down of A
        A_gamma_0: uint256 = self.initial_A_gamma
        t0: uint256 = self.initial_A_gamma_time

        # Less readable but more compact way of writing and converting to uint256
        # gamma0: uint256 = bitwise_and(A_gamma_0, 2**128-1)
        # A0: uint256 = shift(A_gamma_0, -128)
        # A1 = A0 + (A1 - A0) * (block.timestamp - t0) / (t1 - t0)
        # gamma1 = gamma0 + (gamma1 - gamma0) * (block.timestamp - t0) / (t1 - t0)

        t1 -= t0
        t0 = block.timestamp - t0
        t2: uint256 = t1 - t0

        A1 = (shift(A_gamma_0, -128) * t2 + A1 * t0) / t1
        gamma1 = (bitwise_and(A_gamma_0, 2**128-1) * t2 + gamma1 * t0) / t1

    return [A1, gamma1]


@view
@external
def A() -> uint256:
    return self._A_gamma()[0]


@view
@external
def gamma() -> uint256:
    return self._A_gamma()[1]


@internal
@view
def _fee(xp: uint256[N_COINS]) -> uint256:
    f: uint256 = Math(math).reduction_coefficient(xp, self.fee_gamma)
    return (self.mid_fee * f + self.out_fee * (10**18 - f)) / 10**18


@external
@view
def fee() -> uint256:
    return self._fee(self.xp())


@external
@view
def fee_calc(xp: uint256[N_COINS]) -> uint256:
    return self._fee(xp)


@internal
@view
def get_xcp(D: uint256) -> uint256:
    x: uint256[N_COINS] = empty(uint256[N_COINS])
    x[0] = D / N_COINS
    packed_prices: uint256 = self.price_scale_packed
    # No precisions here because we don't switch to "real" units

    for i in range(1, N_COINS):
        x[i] = D * 10**18 / (N_COINS * bitwise_and(packed_prices, PRICE_MASK))  # ... * PRICE_PRECISION_MUL)
        packed_prices = shift(packed_prices, -PRICE_SIZE)

    return Math(math).geometric_mean(x)


@external
@view
def get_virtual_price() -> uint256:
    return 10**18 * self.get_xcp(self.D) / CurveToken(token).totalSupply()


@internal
def _claim_admin_fees():
    A_gamma: uint256[2] = self._A_gamma()

    xcp_profit: uint256 = self.xcp_profit
    xcp_profit_a: uint256 = self.xcp_profit_a

    # Gulp here
    _coins: address[N_COINS] = coins
    for i in range(N_COINS):
        self.balances[i] = ERC20(_coins[i]).balanceOf(self)

    vprice: uint256 = self.virtual_price

    if xcp_profit > xcp_profit_a:
        fees: uint256 = (xcp_profit - xcp_profit_a) * self.admin_fee / (2 * 10**10)
        if fees > 0:
            receiver: address = self.admin_fee_receiver
            frac: uint256 = vprice * 10**18 / (vprice - fees) - 10**18
            claimed: uint256 = CurveToken(token).mint_relative(receiver, frac)
            xcp_profit -= fees*2
            self.xcp_profit = xcp_profit
            log ClaimAdminFee(receiver, claimed)

    total_supply: uint256 = CurveToken(token).totalSupply()

    # Recalculate D b/c we gulped
    D: uint256 = Math(math).newton_D(A_gamma[0], A_gamma[1], self.xp())
    self.D = D

    self.virtual_price = 10**18 * self.get_xcp(D) / total_supply

    if xcp_profit > xcp_profit_a:
        self.xcp_profit_a = xcp_profit


@internal
def tweak_price(A_gamma: uint256[2],
                _xp: uint256[N_COINS], i: uint256, p_i: uint256,
                new_D: uint256):
    price_oracle: uint256[N_COINS-1] = empty(uint256[N_COINS-1])
    last_prices: uint256[N_COINS-1] = empty(uint256[N_COINS-1])
    price_scale: uint256[N_COINS-1] = empty(uint256[N_COINS-1])
    xp: uint256[N_COINS] = empty(uint256[N_COINS])
    p_new: uint256[N_COINS-1] = empty(uint256[N_COINS-1])

    # Update MA if needed
    packed_prices: uint256 = self.price_oracle_packed
    for k in range(N_COINS-1):
        price_oracle[k] = bitwise_and(packed_prices, PRICE_MASK)  # * PRICE_PRECISION_MUL
        packed_prices = shift(packed_prices, -PRICE_SIZE)

    last_prices_timestamp: uint256 = self.last_prices_timestamp
    packed_prices = self.last_prices_packed
    for k in range(N_COINS-1):
        last_prices[k] = bitwise_and(packed_prices, PRICE_MASK)   # * PRICE_PRECISION_MUL
        packed_prices = shift(packed_prices, -PRICE_SIZE)

    if last_prices_timestamp < block.timestamp:
        # MA update required
        ma_half_time: uint256 = self.ma_half_time
        alpha: uint256 = Math(math).halfpow((block.timestamp - last_prices_timestamp) * 10**18 / ma_half_time, 10**10)
        packed_prices = 0
        for k in range(N_COINS-1):
            price_oracle[k] = (last_prices[k] * (10**18 - alpha) + price_oracle[k] * alpha) / 10**18
        for k in range(N_COINS-1):
            packed_prices = shift(packed_prices, PRICE_SIZE)
            p: uint256 = price_oracle[N_COINS-2 - k]  # / PRICE_PRECISION_MUL
            assert p < PRICE_MASK
            packed_prices = bitwise_or(p, packed_prices)
        self.price_oracle_packed = packed_prices
        self.last_prices_timestamp = block.timestamp

    D_unadjusted: uint256 = new_D  # Withdrawal methods know new D already
    if new_D == 0:
        # We will need this a few times (35k gas)
        D_unadjusted = Math(math).newton_D(A_gamma[0], A_gamma[1], _xp)
    packed_prices = self.price_scale_packed
    for k in range(N_COINS-1):
        price_scale[k] = bitwise_and(packed_prices, PRICE_MASK)  # * PRICE_PRECISION_MUL
        packed_prices = shift(packed_prices, -PRICE_SIZE)

    if p_i > 0:
        # Save the last price
        if i > 0:
            last_prices[i-1] = p_i
        else:
            # If 0th price changed - change all prices instead
            for k in range(N_COINS-1):
                last_prices[k] = last_prices[k] * 10**18 / p_i
    else:
        # calculate real prices
        # it would cost 70k gas for a 3-token pool. Sad. How do we do better?
        __xp: uint256[N_COINS] = _xp
        dx_price: uint256 = __xp[0] / 10**6
        __xp[0] += dx_price
        for k in range(N_COINS-1):
            last_prices[k] = price_scale[k] * dx_price / (_xp[k+1] - Math(math).newton_y(A_gamma[0], A_gamma[1], __xp, D_unadjusted, k+1))

    packed_prices = 0
    for k in range(N_COINS-1):
        packed_prices = shift(packed_prices, PRICE_SIZE)
        p: uint256 = last_prices[N_COINS-2 - k]  # / PRICE_PRECISION_MUL
        assert p < PRICE_MASK
        packed_prices = bitwise_or(p, packed_prices)
    self.last_prices_packed = packed_prices

    total_supply: uint256 = CurveToken(token).totalSupply()
    old_xcp_profit: uint256 = self.xcp_profit
    old_virtual_price: uint256 = self.virtual_price

    # Update profit numbers without price adjustment first
    xp[0] = D_unadjusted / N_COINS
    for k in range(N_COINS-1):
        xp[k+1] = D_unadjusted * 10**18 / (N_COINS * price_scale[k])
    xcp_profit: uint256 = 10**18
    virtual_price: uint256 = 10**18

    if old_virtual_price > 0:
        xcp: uint256 = Math(math).geometric_mean(xp)
        virtual_price = 10**18 * xcp / total_supply
        xcp_profit = old_xcp_profit * virtual_price / old_virtual_price

        t: uint256 = self.future_A_gamma_time
        if virtual_price < old_virtual_price and t == 0:
            raise "Loss"
        if t == 1:
            self.future_A_gamma_time = 0

    self.xcp_profit = xcp_profit

    needs_adjustment: bool = self.not_adjusted
    # if not needs_adjustment and (virtual_price-10**18 > (xcp_profit-10**18)/2 + self.allowed_extra_profit):
    # (re-arrange for gas efficiency)
    if not needs_adjustment and (virtual_price * 2 - 10**18 > xcp_profit + 2*self.allowed_extra_profit):
        needs_adjustment = True
        self.not_adjusted = True

    if needs_adjustment:
        adjustment_step: uint256 = self.adjustment_step
        norm: uint256 = 0

        for k in range(N_COINS-1):
            ratio: uint256 = price_oracle[k] * 10**18 / price_scale[k]
            if ratio > 10**18:
                ratio -= 10**18
            else:
                ratio = 10**18 - ratio
            norm += ratio**2

        if norm > adjustment_step ** 2 and old_virtual_price > 0:
            norm = Math(math).sqrt_int(norm / 10**18)  # Need to convert to 1e18 units!

            for k in range(N_COINS-1):
                p_new[k] = (price_scale[k] * (norm - adjustment_step) + adjustment_step * price_oracle[k]) / norm

            # Calculate balances*prices
            xp = _xp
            for k in range(N_COINS-1):
                xp[k+1] = _xp[k+1] * p_new[k] / price_scale[k]

            # Calculate "extended constant product" invariant xCP and virtual price
            D: uint256 = Math(math).newton_D(A_gamma[0], A_gamma[1], xp)
            xp[0] = D / N_COINS
            for k in range(N_COINS-1):
                xp[k+1] = D * 10**18 / (N_COINS * p_new[k])
            # We reuse old_virtual_price here but it's not old anymore
            old_virtual_price = 10**18 * Math(math).geometric_mean(xp) / total_supply

            # Proceed if we've got enough profit
            # if (old_virtual_price > 10**18) and (2 * (old_virtual_price - 10**18) > xcp_profit - 10**18):
            if (old_virtual_price > 10**18) and (2 * old_virtual_price - 10**18 > xcp_profit):
                packed_prices = 0
                for k in range(N_COINS-1):
                    packed_prices = shift(packed_prices, PRICE_SIZE)
                    p: uint256 = p_new[N_COINS-2 - k]  # / PRICE_PRECISION_MUL
                    assert p < PRICE_MASK
                    packed_prices = bitwise_or(p, packed_prices)
                self.price_scale_packed = packed_prices
                self.D = D
                self.virtual_price = old_virtual_price

                return

            else:
                self.not_adjusted = False

    # If we are here, the price_scale adjustment did not happen
    # Still need to update the profit counter and D
    self.D = D_unadjusted
    self.virtual_price = virtual_price



@payable
@external
@nonreentrant('lock')
def exchange(i: uint256, j: uint256, dx: uint256, min_dy: uint256, use_eth: bool = False):
    assert not self.is_killed  # dev: the pool is killed
    assert i != j  # dev: coin index out of range
    assert i < N_COINS  # dev: coin index out of range
    assert j < N_COINS  # dev: coin index out of range
    assert dx > 0  # dev: do not exchange 0 coins

    A_gamma: uint256[2] = self._A_gamma()
    xp: uint256[N_COINS] = self.balances
    ix: uint256 = j
    p: uint256 = 0
    dy: uint256 = 0

    if True:  # scope to reduce size of memory when making internal calls later
        _coins: address[N_COINS] = coins
        if i == 2 and use_eth:
            assert msg.value == dx  # dev: incorrect eth amount
            WETH(coins[2]).deposit(value=msg.value)
        else:
            assert msg.value == 0  # dev: nonzero eth amount
            # assert might be needed for some tokens - removed one to save bytespace
            ERC20(_coins[i]).transferFrom(msg.sender, self, dx)

        y: uint256 = xp[j]
        x0: uint256 = xp[i]
        xp[i] = x0 + dx
        self.balances[i] = xp[i]

        price_scale: uint256[N_COINS-1] = empty(uint256[N_COINS-1])
        packed_prices: uint256 = self.price_scale_packed
        for k in range(N_COINS-1):
            price_scale[k] = bitwise_and(packed_prices, PRICE_MASK)  # * PRICE_PRECISION_MUL
            packed_prices = shift(packed_prices, -PRICE_SIZE)

        precisions: uint256[N_COINS] = PRECISIONS
        xp[0] *= PRECISIONS[0]
        for k in range(1, N_COINS):
            xp[k] = xp[k] * price_scale[k-1] * precisions[k] / PRECISION

        prec_i: uint256 = precisions[i]

        # In case ramp is happening
        if True:
            t: uint256 = self.future_A_gamma_time
            if t > 0:
                x0 *= prec_i
                if i > 0:
                    x0 = x0 * price_scale[i-1] / PRECISION
                x1: uint256 = xp[i]  # Back up old value in xp
                xp[i] = x0
                self.D = Math(math).newton_D(A_gamma[0], A_gamma[1], xp)
                xp[i] = x1  # And restore
                if block.timestamp >= t:
                    self.future_A_gamma_time = 1

        prec_j: uint256 = precisions[j]

        dy = xp[j] - Math(math).newton_y(A_gamma[0], A_gamma[1], xp, self.D, j)
        # Not defining new "y" here to have less variables / make subsequent calls cheaper
        xp[j] -= dy
        dy -= 1

        if j > 0:
            dy = dy * PRECISION / price_scale[j-1]
        dy /= prec_j

        dy -= self._fee(xp) * dy / 10**10
        assert dy >= min_dy, "Slippage"
        y -= dy

        self.balances[j] = y
        # assert might be needed for some tokens - removed one to save bytespace
        if j == 2 and use_eth:
            WETH(coins[2]).withdraw(dy)
            raw_call(msg.sender, b"", value=dy)
        else:
            ERC20(_coins[j]).transfer(msg.sender, dy)

        y *= prec_j
        if j > 0:
            y = y * price_scale[j-1] / PRECISION
        xp[j] = y

        # Calculate price
        if dx > 10**5 and dy > 10**5:
            _dx: uint256 = dx * prec_i
            _dy: uint256 = dy * prec_j
            if i != 0 and j != 0:
                p = bitwise_and(
                    shift(self.last_prices_packed, -PRICE_SIZE * convert(i-1, int256)),
                    PRICE_MASK
                ) * _dx / _dy  # * PRICE_PRECISION_MUL
            elif i == 0:
                p = _dx * 10**18 / _dy
            else:  # j == 0
                p = _dy * 10**18 / _dx
                ix = i

    self.tweak_price(A_gamma, xp, ix, p, 0)

    log TokenExchange(msg.sender, i, dx, j, dy)


@external
@view
def get_dy(i: uint256, j: uint256, dx: uint256) -> uint256:
    return Views(views).get_dy(i, j, dx)


@view
@internal
def _calc_token_fee(amounts: uint256[N_COINS], xp: uint256[N_COINS]) -> uint256:
    # fee = sum(amounts_i - avg(amounts)) * fee' / sum(amounts)
    fee: uint256 = self._fee(xp) * N_COINS / (4 * (N_COINS-1))
    S: uint256 = 0
    for _x in amounts:
        S += _x
    avg: uint256 = S / N_COINS
    Sdiff: uint256 = 0
    for _x in amounts:
        if _x > avg:
            Sdiff += _x - avg
        else:
            Sdiff += avg - _x
    return fee * Sdiff / S + NOISE_FEE


@external
@view
def calc_token_fee(amounts: uint256[N_COINS], xp: uint256[N_COINS]) -> uint256:
    return self._calc_token_fee(amounts, xp)


@external
@nonreentrant('lock')
def add_liquidity(amounts: uint256[N_COINS], min_mint_amount: uint256):
    assert not self.is_killed  # dev: the pool is killed

    A_gamma: uint256[2] = self._A_gamma()

    _coins: address[N_COINS] = coins

    xp: uint256[N_COINS] = self.balances
    amountsp: uint256[N_COINS] = empty(uint256[N_COINS])
    xx: uint256[N_COINS] = empty(uint256[N_COINS])
    d_token: uint256 = 0
    d_token_fee: uint256 = 0
    old_D: uint256 = 0
    ix: uint256 = INF_COINS

    if True:  # Scope to avoid having extra variables in memory later
        xp_old: uint256[N_COINS] = xp

        for i in range(N_COINS):
            bal: uint256 = xp[i] + amounts[i]
            xp[i] = bal
            self.balances[i] = bal
        xx = xp

        precisions: uint256[N_COINS] = PRECISIONS
        packed_prices: uint256 = self.price_scale_packed
        xp[0] *= PRECISIONS[0]
        xp_old[0] *= PRECISIONS[0]
        for i in range(1, N_COINS):
            price_scale: uint256 = bitwise_and(packed_prices, PRICE_MASK) * precisions[i]  # * PRICE_PRECISION_MUL
            xp[i] = xp[i] * price_scale / PRECISION
            xp_old[i] = xp_old[i] * price_scale / PRECISION
            packed_prices = shift(packed_prices, -PRICE_SIZE)

        for i in range(N_COINS):
            if amounts[i] > 0:
                # assert might be needed for some tokens - removed one to save bytespace
                ERC20(_coins[i]).transferFrom(msg.sender, self, amounts[i])
                amountsp[i] = xp[i] - xp_old[i]
                if ix == INF_COINS:
                    ix = i
                else:
                    ix = INF_COINS-1
        assert ix != INF_COINS  # dev: no coins to add

        t: uint256 = self.future_A_gamma_time
        if t > 0:
            old_D = Math(math).newton_D(A_gamma[0], A_gamma[1], xp_old)
            if block.timestamp >= t:
                self.future_A_gamma_time = 1
        else:
            old_D = self.D

    D: uint256 = Math(math).newton_D(A_gamma[0], A_gamma[1], xp)

    token_supply: uint256 = CurveToken(token).totalSupply()
    if old_D > 0:
        d_token = token_supply * D / old_D - token_supply
    else:
        d_token = self.get_xcp(D)  # making initial virtual price equal to 1
    assert d_token > 0  # dev: nothing minted

    if old_D > 0:
        d_token_fee = self._calc_token_fee(amountsp, xp) * d_token / 10**10 + 1
        d_token -= d_token_fee
        token_supply += d_token
        CurveToken(token).mint(msg.sender, d_token)

        # Calculate price
        # p_i * (dx_i - dtoken / token_supply * xx_i) = sum{k!=i}(p_k * (dtoken / token_supply * xx_k - dx_k))
        # Only ix is nonzero
        p: uint256 = 0
        if d_token > 10**5:
            if ix < N_COINS:
                S: uint256 = 0
                last_prices: uint256[N_COINS-1] = empty(uint256[N_COINS-1])
                packed_prices: uint256 = self.last_prices_packed
                precisions: uint256[N_COINS] = PRECISIONS
                for k in range(N_COINS-1):
                    last_prices[k] = bitwise_and(packed_prices, PRICE_MASK)  # * PRICE_PRECISION_MUL
                    packed_prices = shift(packed_prices, -PRICE_SIZE)
                for i in range(N_COINS):
                    if i != ix:
                        if i == 0:
                            S += xx[0] * PRECISIONS[0]
                        else:
                            S += xx[i] * last_prices[i-1] * precisions[i] / PRECISION
                S = S * d_token / token_supply
                p = S * PRECISION / (amounts[ix] * precisions[ix] - d_token * xx[ix] * precisions[ix] / token_supply)

        self.tweak_price(A_gamma, xp, ix, p, D)

    else:
        self.D = D
        self.virtual_price = 10**18
        self.xcp_profit = 10**18
        CurveToken(token).mint(msg.sender, d_token)

    assert d_token >= min_mint_amount, "Slippage"

    log AddLiquidity(msg.sender, amounts, d_token_fee, token_supply)


@external
@nonreentrant('lock')
def remove_liquidity(_amount: uint256, min_amounts: uint256[N_COINS]):
    """
    This withdrawal method is very safe, does no complex math
    """
    _coins: address[N_COINS] = coins
    total_supply: uint256 = CurveToken(token).totalSupply()
    CurveToken(token).burnFrom(msg.sender, _amount)
    balances: uint256[N_COINS] = self.balances
    amount: uint256 = _amount - 1  # Make rounding errors favoring other LPs a tiny bit

    for i in range(N_COINS):
        d_balance: uint256 = balances[i] * amount / total_supply
        assert d_balance >= min_amounts[i]
        self.balances[i] = balances[i] - d_balance
        balances[i] = d_balance  # now it's the amounts going out
        # assert might be needed for some tokens - removed one to save bytespace
        ERC20(_coins[i]).transfer(msg.sender, d_balance)

    D: uint256 = self.D
    self.D = D - D * amount / total_supply

    log RemoveLiquidity(msg.sender, balances, total_supply - _amount)


@view
@external
def calc_token_amount(amounts: uint256[N_COINS], deposit: bool) -> uint256:
    return Views(views).calc_token_amount(amounts, deposit)


@internal
@view
def _calc_withdraw_one_coin(A_gamma: uint256[2], token_amount: uint256, i: uint256, update_D: bool,
                            calc_price: bool) -> (uint256, uint256, uint256, uint256[N_COINS]):
    token_supply: uint256 = CurveToken(token).totalSupply()
    assert token_amount <= token_supply  # dev: token amount more than supply
    assert i < N_COINS  # dev: coin out of range

    xx: uint256[N_COINS] = self.balances
    xp: uint256[N_COINS] = PRECISIONS
    D0: uint256 = 0

    price_scale_i: uint256 = PRECISION * PRECISIONS[0]
    if True:  # To remove packed_prices from memory
        packed_prices: uint256 = self.price_scale_packed
        xp[0] *= xx[0]
        for k in range(1, N_COINS):
            p: uint256 = bitwise_and(packed_prices, PRICE_MASK)  # * PRICE_PRECISION_MUL
            if i == k:
                price_scale_i = p * xp[i]
            xp[k] = xp[k] * xx[k] * p / PRECISION
            packed_prices = shift(packed_prices, -PRICE_SIZE)

    if update_D:
        D0 = Math(math).newton_D(A_gamma[0], A_gamma[1], xp)
    else:
        D0 = self.D

    D: uint256 = D0

    # Charge the fee on D, not on y, e.g. reducing invariant LESS than charging the user
    fee: uint256 = self._fee(xp)
    dD: uint256 = token_amount * D / token_supply
    D -= (dD - (fee * dD / (2 * 10**10) + 1))
    y: uint256 = Math(math).newton_y(A_gamma[0], A_gamma[1], xp, D, i)
    dy: uint256 = (xp[i] - y) * PRECISION / price_scale_i
    xp[i] = y

    # Price calc
    p: uint256 = 0
    if calc_price and dy > 10**5 and token_amount > 10**5:
        # p_i = dD / D0 * sum'(p_k * x_k) / (dy - dD / D0 * y0)
        S: uint256 = 0
        precisions: uint256[N_COINS] = PRECISIONS
        last_prices: uint256[N_COINS-1] = empty(uint256[N_COINS-1])
        packed_prices: uint256 = self.last_prices_packed
        for k in range(N_COINS-1):
            last_prices[k] = bitwise_and(packed_prices, PRICE_MASK)  # * PRICE_PRECISION_MUL
            packed_prices = shift(packed_prices, -PRICE_SIZE)
        for k in range(N_COINS):
            if k != i:
                if k == 0:
                    S += xx[0] * PRECISIONS[0]
                else:
                    S += xx[k] * last_prices[k-1] * precisions[k] / PRECISION
        S = S * dD / D0
        p = S * PRECISION / (dy * precisions[i] - dD * xx[i] * precisions[i] / D0)

    return dy, p, D, xp


@view
@external
def calc_withdraw_one_coin(token_amount: uint256, i: uint256) -> uint256:
    return self._calc_withdraw_one_coin(self._A_gamma(), token_amount, i, True, False)[0]


@external
@nonreentrant('lock')
def remove_liquidity_one_coin(token_amount: uint256, i: uint256, min_amount: uint256):
    assert not self.is_killed  # dev: the pool is killed

    A_gamma: uint256[2] = self._A_gamma()

    dy: uint256 = 0
    D: uint256 = 0
    p: uint256 = 0
    xp: uint256[N_COINS] = empty(uint256[N_COINS])
    future_A_gamma_time: uint256 = self.future_A_gamma_time
    dy, p, D, xp = self._calc_withdraw_one_coin(A_gamma, token_amount, i, (future_A_gamma_time > 0), True)
    assert dy >= min_amount, "Slippage"

    if block.timestamp >= future_A_gamma_time:
        self.future_A_gamma_time = 1

    self.balances[i] -= dy
    CurveToken(token).burnFrom(msg.sender, token_amount)
    self.tweak_price(A_gamma, xp, i, p, D)

    _coins: address[N_COINS] = coins
    # assert might be needed for some tokens - removed one to save bytespace
    ERC20(_coins[i]).transfer(msg.sender, dy)

    log RemoveLiquidityOne(msg.sender, token_amount, i, dy)


@external
@nonreentrant('lock')
def claim_admin_fees():
    self._claim_admin_fees()


# Admin parameters
@external
def ramp_A_gamma(future_A: uint256, future_gamma: uint256, future_time: uint256):
    assert msg.sender == self.owner  # dev: only owner
    assert block.timestamp > self.initial_A_gamma_time + (MIN_RAMP_TIME-1)
    assert future_time > block.timestamp + (MIN_RAMP_TIME-1)  # dev: insufficient time

    A_gamma: uint256[2] = self._A_gamma()
    initial_A_gamma: uint256 = shift(A_gamma[0], 128)
    initial_A_gamma = bitwise_or(initial_A_gamma, A_gamma[1])

    assert future_A > 0
    assert future_A < MAX_A+1
    assert future_gamma > MIN_GAMMA-1
    assert future_gamma < MAX_GAMMA+1

    ratio: uint256 = 10**18 * future_A / A_gamma[0]
    assert ratio < 10**18 * MAX_A_CHANGE + 1
    assert ratio > 10**18 / MAX_A_CHANGE - 1

    ratio = 10**18 * future_gamma / A_gamma[1]
    assert ratio < 10**18 * MAX_A_CHANGE + 1
    assert ratio > 10**18 / MAX_A_CHANGE - 1

    self.initial_A_gamma = initial_A_gamma
    self.initial_A_gamma_time = block.timestamp

    future_A_gamma: uint256 = shift(future_A, 128)
    future_A_gamma = bitwise_or(future_A_gamma, future_gamma)
    self.future_A_gamma_time = future_time
    self.future_A_gamma = future_A_gamma

    log RampAgamma(A_gamma[0], future_A, A_gamma[1], future_gamma, block.timestamp, future_time)


@external
def stop_ramp_A_gamma():
    assert msg.sender == self.owner  # dev: only owner

    A_gamma: uint256[2] = self._A_gamma()
    current_A_gamma: uint256 = shift(A_gamma[0], 128)
    current_A_gamma = bitwise_or(current_A_gamma, A_gamma[1])
    self.initial_A_gamma = current_A_gamma
    self.future_A_gamma = current_A_gamma
    self.initial_A_gamma_time = block.timestamp
    self.future_A_gamma_time = block.timestamp
    # now (block.timestamp < t1) is always False, so we return saved A

    log StopRampA(A_gamma[0], A_gamma[1], block.timestamp)


@external
def commit_new_parameters(
    _new_mid_fee: uint256,
    _new_out_fee: uint256,
    _new_admin_fee: uint256,
    _new_fee_gamma: uint256,
    _new_allowed_extra_profit: uint256,
    _new_adjustment_step: uint256,
    _new_ma_half_time: uint256,
    ):
    assert msg.sender == self.owner  # dev: only owner
    assert self.admin_actions_deadline == 0  # dev: active action

    new_mid_fee: uint256 = _new_mid_fee
    new_out_fee: uint256 = _new_out_fee
    new_admin_fee: uint256 = _new_admin_fee
    new_fee_gamma: uint256 = _new_fee_gamma
    new_allowed_extra_profit: uint256 = _new_allowed_extra_profit
    new_adjustment_step: uint256 = _new_adjustment_step
    new_ma_half_time: uint256 = _new_ma_half_time

    # Fees
    if new_out_fee < MAX_FEE+1:
        assert new_out_fee > MIN_FEE-1  # dev: fee is out of range
    else:
        new_out_fee = self.out_fee
    if new_mid_fee > MAX_FEE:
        new_mid_fee = self.mid_fee
    assert new_mid_fee <= new_out_fee  # dev: mid-fee is too high
    if new_admin_fee > MAX_ADMIN_FEE:
        new_admin_fee = self.admin_fee

    # AMM parameters
    if new_fee_gamma < 10**18:
        assert new_fee_gamma > 0  # dev: fee_gamma out of range [1 .. 10**18]
    else:
        new_fee_gamma = self.fee_gamma
    if new_allowed_extra_profit > 10**18:
        new_allowed_extra_profit = self.allowed_extra_profit
    if new_adjustment_step > 10**18:
        new_adjustment_step = self.adjustment_step

    # MA
    if new_ma_half_time < 7*86400:
        assert new_ma_half_time > 0  # dev: MA time should be longer than 1 second
    else:
        new_ma_half_time = self.ma_half_time

    _deadline: uint256 = block.timestamp + ADMIN_ACTIONS_DELAY
    self.admin_actions_deadline = _deadline

    self.future_admin_fee = new_admin_fee
    self.future_mid_fee = new_mid_fee
    self.future_out_fee = new_out_fee
    self.future_fee_gamma = new_fee_gamma
    self.future_allowed_extra_profit = new_allowed_extra_profit
    self.future_adjustment_step = new_adjustment_step
    self.future_ma_half_time = new_ma_half_time

    log CommitNewParameters(_deadline, new_admin_fee, new_mid_fee, new_out_fee,
                            new_fee_gamma,
                            new_allowed_extra_profit, new_adjustment_step,
                            new_ma_half_time)


@external
@nonreentrant('lock')
def apply_new_parameters():
    assert msg.sender == self.owner  # dev: only owner
    assert block.timestamp >= self.admin_actions_deadline  # dev: insufficient time
    assert self.admin_actions_deadline != 0  # dev: no active action

    self.admin_actions_deadline = 0

    admin_fee: uint256 = self.future_admin_fee
    if self.admin_fee != admin_fee:
        self._claim_admin_fees()
        self.admin_fee = admin_fee

    mid_fee: uint256 = self.future_mid_fee
    self.mid_fee = mid_fee
    out_fee: uint256 = self.future_out_fee
    self.out_fee = out_fee
    fee_gamma: uint256 = self.future_fee_gamma
    self.fee_gamma = fee_gamma
    allowed_extra_profit: uint256 = self.future_allowed_extra_profit
    self.allowed_extra_profit = allowed_extra_profit
    adjustment_step: uint256 = self.future_adjustment_step
    self.adjustment_step = adjustment_step
    ma_half_time: uint256 = self.future_ma_half_time
    self.ma_half_time = ma_half_time

    log NewParameters(admin_fee, mid_fee, out_fee,
                      fee_gamma,
                      allowed_extra_profit, adjustment_step,
                      ma_half_time)


@external
def revert_new_parameters():
    assert msg.sender == self.owner  # dev: only owner

    self.admin_actions_deadline = 0


@external
def commit_transfer_ownership(_owner: address):
    assert msg.sender == self.owner  # dev: only owner
    assert self.transfer_ownership_deadline == 0  # dev: active transfer

    _deadline: uint256 = block.timestamp + ADMIN_ACTIONS_DELAY
    self.transfer_ownership_deadline = _deadline
    self.future_owner = _owner

    log CommitNewAdmin(_deadline, _owner)


@external
def apply_transfer_ownership():
    assert msg.sender == self.owner  # dev: only owner
    assert block.timestamp >= self.transfer_ownership_deadline  # dev: insufficient time
    assert self.transfer_ownership_deadline != 0  # dev: no active transfer

    self.transfer_ownership_deadline = 0
    _owner: address = self.future_owner
    self.owner = _owner

    log NewAdmin(_owner)


@external
def revert_transfer_ownership():
    assert msg.sender == self.owner  # dev: only owner

    self.transfer_ownership_deadline = 0


@external
def kill_me():
    assert msg.sender == self.owner  # dev: only owner
    assert self.kill_deadline > block.timestamp  # dev: deadline has passed
    self.is_killed = True


@external
def unkill_me():
    assert msg.sender == self.owner  # dev: only owner
    self.is_killed = False


@external
def set_admin_fee_receiver(_admin_fee_receiver: address):
    assert msg.sender == self.owner  # dev: only owner
    self.admin_fee_receiver = _admin_fee_receiver

# @version 0.2.16

interface AddressProvider:
    def get_registry() -> address: view
    def get_address(_id: uint256) -> address: view

interface Registry:
    def find_pool_for_coins(_from: address, _to: address) -> address: view
    def get_coin_indices(
        _pool: address,
        _from: address,
        _to: address
    ) -> (uint256, uint256, uint256): view

interface RegistrySwap:
    def get_best_rate(_from: address, _to: address, _amount: uint256) -> (address, uint256): view

interface CurveCryptoSwap:
    def get_dy(i: uint256, j: uint256, dx: uint256) -> uint256: view
    def exchange(i: uint256, j: uint256, dx: uint256, min_dy: uint256, use_eth: bool): payable
    def coins(i: uint256) -> address: view

interface CurvePool:
    def exchange(i: int128, j: int128, dx: uint256, min_dy: uint256): payable
    def exchange_underlying(i: int128, j: int128, dx: uint256, min_dy: uint256): payable

interface ERC20:
    def approve(spender: address, amount: uint256): nonpayable
    def transfer(to: address, amount: uint256): nonpayable
    def transferFrom(sender: address, to: address, amount: uint256): nonpayable
    def balanceOf(owner: address) -> uint256: view


event CommitOwnership:
    admin: address

event ApplyOwnership:
    admin: address

event TrustedForwardershipTransferred:
    previous_forwarder: address
    new_forwarder: address


ADDRESS_PROVIDER: constant(address) = 0x0000000022D53366457F9d5E68Ec105046FC4383
ETH: constant(address) = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
WETH: constant(address) = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2

swap: public(address)
crypto_coins: public(address[3])

# token -> spender -> is approved to transfer?
is_approved: HashMap[address, HashMap[address, bool]]

owner: public(address)
trusted_forwarder: public(address)

future_owner: public(address)


@external
def __init__(_swap: address):
    self.owner = msg.sender
    self.swap = _swap
    for i in range(3):
        coin: address = CurveCryptoSwap(_swap).coins(i)
        if coin == WETH:
            self.crypto_coins[i] = ETH
        else:
            ERC20(coin).approve(_swap, MAX_UINT256)
            self.crypto_coins[i] = coin


@payable
@external
def __default__():
    # required to receive Ether
    pass


@payable
@external
def exchange(
    _amount: uint256,
    _route: address[6],
    _indices: uint256[8],
    _min_received: uint256,
    _receiver: address = msg.sender
):
    """
    @notice Perform a cross-asset exchange.
    @dev `_route` and `_indices` are generated by calling `get_exchange_routing`
         prior to making a transaction. This reduces gas costs on swaps.
    @param _amount Amount of the input token being swapped.
    @param _route Array of token and pool addresses used within the swap.
    @param _indices Array of `i` and `j` inputs used for individual swaps.
    @param _min_received Minimum amount of the output token to be received. If
                         the actual amount received is less the call will revert.
    @param _receiver An alternate address to which the output of the exchange will be sent
    """
    # Meta-tx support
    msg_sender: address = msg.sender
    receiver: address = _receiver
    if msg_sender == self.trusted_forwarder:
        calldata_len: uint256 = len(msg.data)
        addr_bytes: Bytes[20] = empty(Bytes[20])
        # grab the last 20 bytes of calldata which holds the address
        if calldata_len == 536:
            addr_bytes = slice(msg.data, 516, 20)
        elif calldata_len == 568:
            addr_bytes = slice(msg.data, 548, 20)
        # convert to an address
        msg_sender = convert(convert(addr_bytes, uint256), address)
        if _receiver == msg.sender:
            # we already know that msg.sender is the trusted forwarder
            # if _receiver is set to msg.sender change it to be correct
            receiver = msg_sender

    eth_value: uint256 = 0
    amount: uint256 = _amount

    # perform the first stableswap, if required
    if _route[1] != ZERO_ADDRESS:
        ERC20(_route[0]).transferFrom(msg_sender, self, _amount)  # dev: insufficient amount

        if not self.is_approved[_route[0]][_route[1]]:
            ERC20(_route[0]).approve(_route[1], MAX_UINT256)  # dev: bad response
            self.is_approved[_route[0]][_route[1]] = True

        # `_indices[2]` is a boolean-as-integer indicating if the swap uses `exchange_underlying`
        if _indices[2] == 0:
            CurvePool(_route[1]).exchange(
                convert(_indices[0], int128),
                convert(_indices[1], int128),
                _amount,
                0,
                value=msg.value,
            )  # dev: bad response
        else:
            CurvePool(_route[1]).exchange_underlying(
                convert(_indices[0], int128),
                convert(_indices[1], int128),
                _amount,
                0,
                value=msg.value,
            )  # dev: bad response

        if _route[2] == ETH:
            amount = self.balance
            eth_value = self.balance
        else:
            amount = ERC20(_route[2]).balanceOf(self)  # dev: bad response

    # if no initial stableswap, transfer token and validate the amount of ether sent
    elif _route[2] == ETH:
        assert _amount == msg.value  # dev: insufficient amount
        eth_value = msg.value
    else:
        assert msg.value == 0
        ERC20(_route[2]).transferFrom(msg_sender, self, _amount)  # dev: insufficient amount

    # perform the main crypto swap, if required
    if _indices[3] != _indices[4]:
        use_eth: bool = ETH in [_route[2], _route[3]]
        CurveCryptoSwap(self.swap).exchange(
            _indices[3],
            _indices[4],
            amount,
            0,
            use_eth,
            value=eth_value
        )  # dev: bad response
        if _route[3] == ETH:
            amount = self.balance
            eth_value = self.balance
        else:
            amount = ERC20(_route[3]).balanceOf(self)  # dev: bad response
            eth_value = 0

    # perform the second stableswap, if required
    if _route[4] != ZERO_ADDRESS:
        if _route[3] != ETH and not self.is_approved[_route[3]][_route[4]]:
            ERC20(_route[3]).approve(_route[4], MAX_UINT256)  # dev: bad response
            self.is_approved[_route[3]][_route[4]] = True

        # `_indices[7]` is a boolean-as-integer indicating if the swap uses `exchange_underlying`
        if _indices[7] == 0:
            CurvePool(_route[4]).exchange(
                convert(_indices[5], int128),
                convert(_indices[6], int128),
                amount,
                _min_received,
                value=eth_value,
            )  # dev: bad response
        else:
            CurvePool(_route[4]).exchange_underlying(
                convert(_indices[5], int128),
                convert(_indices[6], int128),
                amount,
                _min_received,
                value=eth_value,
            )  # dev: bad response

        if _route[5] == ETH:
            raw_call(receiver, b"", value=self.balance)
        else:
            amount = ERC20(_route[5]).balanceOf(self)
            ERC20(_route[5]).transfer(receiver, amount)

    # if no final swap, check slippage and transfer to receiver
    else:
        assert amount >= _min_received
        if _route[3] == ETH:
            raw_call(receiver, b"", value=self.balance)
        else:
            ERC20(_route[3]).transfer(receiver, amount)


@view
@external
def get_exchange_routing(
    _initial: address,
    _target: address,
    _amount: uint256
) -> (address[6], uint256[8], uint256):
    """
    @notice Get routing data for a cross-asset exchange.
    @dev Outputs from this function are used as inputs when calling `exchange`.
    @param _initial Address of the initial token being swapped.
    @param _target Address of the token to be received in the swap.
    @param _amount Amount of `_initial` to swap.
    @return _route Array of token and pool addresses used within the swap,
                    Array of `i` and `j` inputs used for individual swaps.
                    Expected amount of the output token to be received.
    """

    # route is [initial coin, stableswap, cryptopool input, cryptopool output, stableswap, target coin]
    route: address[6] = empty(address[6])

    # indices is [(i, j, is_underlying), (i, j), (i, j, is_underlying)]
    # tuples indicate first stableswap, crypto swap, second stableswap
    indices: uint256[8] = empty(uint256[8])

    crypto_input: address = ZERO_ADDRESS
    crypto_output: address = ZERO_ADDRESS
    market: address = ZERO_ADDRESS

    amount: uint256 = _amount
    crypto_coins: address[3] = self.crypto_coins
    swaps: address = AddressProvider(ADDRESS_PROVIDER).get_address(2)
    registry: address = AddressProvider(ADDRESS_PROVIDER).get_registry()

    # if initial coin is not in the crypto pool, get info for the first stableswap
    if _initial in crypto_coins:
        crypto_input = _initial
    else:
        received: uint256 = 0
        for coin in crypto_coins:
            market, received = RegistrySwap(swaps).get_best_rate(_initial, coin, amount)
            if market != ZERO_ADDRESS:
                indices[0], indices[1], indices[2] = Registry(registry).get_coin_indices(market, _initial, coin)
                route[0] = _initial
                route[1] = market
                crypto_input = coin
                amount = received
                break
        assert market != ZERO_ADDRESS

    # determine target coin when swapping in the crypto pool
    if _target in crypto_coins:
        crypto_output = _target
    else:
        for coin in crypto_coins:
            if Registry(registry).find_pool_for_coins(coin, _target) != ZERO_ADDRESS:
                crypto_output = coin
                break
        assert crypto_output != ZERO_ADDRESS

    route[2] = crypto_input
    route[3] = crypto_output

    # get i, j and dy for crypto swap if needed
    if crypto_input != crypto_output:
        for x in range(3):
            coin: address = self.crypto_coins[x]
            if coin == crypto_input:
                indices[3] = x
            elif coin == crypto_output:
                indices[4] = x
        amount = CurveCryptoSwap(self.swap).get_dy(indices[3], indices[4], amount)

    # if target coin is not in the crypto pool, get info for the final stableswap
    if crypto_output != _target:
        market, amount = RegistrySwap(swaps).get_best_rate(crypto_output, _target, amount)
        indices[5], indices[6], indices[7] = Registry(registry).get_coin_indices(market, crypto_output, _target)
        route[4] = market
        route[5] = _target

    return route, indices, amount


@view
@external
def can_route(_initial: address, _target: address) -> bool:
    """
    @notice Check if a route is available between two tokens.
    @param _initial Address of the initial token being swapped.
    @param _target Address of the token to be received in the swap.
    @return bool Is route available?
    """

    crypto_coins: address[3] = self.crypto_coins
    registry: address = AddressProvider(ADDRESS_PROVIDER).get_registry()

    crypto_input: address = _initial
    if _initial not in crypto_coins:
        market: address = ZERO_ADDRESS
        for coin in crypto_coins:
            market = Registry(registry).find_pool_for_coins(_initial, coin)
            if market != ZERO_ADDRESS:
                crypto_input = coin
                break
        if market == ZERO_ADDRESS:
            return False

    crypto_output: address = _target
    if _target not in crypto_coins:
        market: address = ZERO_ADDRESS
        for coin in crypto_coins:
            market = Registry(registry).find_pool_for_coins(coin, _target)
            if market != ZERO_ADDRESS:
                crypto_output = coin
                break
        if market == ZERO_ADDRESS:
            return False

    return True


@external
def commit_transfer_ownership(addr: address):
    """
    @notice Transfer ownership of GaugeController to `addr`
    @param addr Address to have ownership transferred to
    """
    assert msg.sender == self.owner  # dev: admin only

    self.future_owner = addr
    log CommitOwnership(addr)


@external
def accept_transfer_ownership():
    """
    @notice Accept a pending ownership transfer
    """
    _admin: address = self.future_owner
    assert msg.sender == _admin  # dev: future admin only

    self.owner = _admin
    log ApplyOwnership(_admin)


@view
@external
def isTrustedForwarder(_forwarder: address) -> bool:
    """
    @notice ERC-2771 meta-txs discovery mechanism
    @param _forwarder Address to compare against the set trusted forwarder
    @return bool True if `_forwarder` equals the set trusted forwarder
    """
    return _forwarder == self.trusted_forwarder


@external
def set_trusted_forwarder(_forwarder: address) -> bool:
    """
    @notice Set the trusted forwarder address
    @param _forwarder The address of the trusted forwarder
    @return bool True on successful execution
    """
    assert msg.sender == self.owner

    prev_forwarder: address = self.trusted_forwarder
    self.trusted_forwarder = _forwarder

    log TrustedForwardershipTransferred(prev_forwarder, _forwarder)
    return True

pragma solidity ^0.4.17;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        assert(c / a == b);
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c >= a);
        return c;
    }
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address public owner;

    /**
      * @dev The Ownable constructor sets the original `owner` of the contract to the sender
      * account.
      */
    function Ownable() public {
        owner = msg.sender;
    }

    /**
      * @dev Throws if called by any account other than the owner.
      */
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    /**
    * @dev Allows the current owner to transfer control of the contract to a newOwner.
    * @param newOwner The address to transfer ownership to.
    */
    function transferOwnership(address newOwner) public onlyOwner {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }

}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20Basic {
    uint public _totalSupply;
    function totalSupply() public constant returns (uint);
    function balanceOf(address who) public constant returns (uint);
    function transfer(address to, uint value) public;
    event Transfer(address indexed from, address indexed to, uint value);
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public constant returns (uint);
    function transferFrom(address from, address to, uint value) public;
    function approve(address spender, uint value) public;
    event Approval(address indexed owner, address indexed spender, uint value);
}

/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is Ownable, ERC20Basic {
    using SafeMath for uint;

    mapping(address => uint) public balances;

    // additional variables for use if transaction fees ever became necessary
    uint public basisPointsRate = 0;
    uint public maximumFee = 0;

    /**
    * @dev Fix for the ERC20 short address attack.
    */
    modifier onlyPayloadSize(uint size) {
        require(!(msg.data.length < size + 4));
        _;
    }

    /**
    * @dev transfer token for a specified address
    * @param _to The address to transfer to.
    * @param _value The amount to be transferred.
    */
    function transfer(address _to, uint _value) public onlyPayloadSize(2 * 32) {
        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        uint sendAmount = _value.sub(fee);
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(msg.sender, owner, fee);
        }
        Transfer(msg.sender, _to, sendAmount);
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param _owner The address to query the the balance of.
    * @return An uint representing the amount owned by the passed address.
    */
    function balanceOf(address _owner) public constant returns (uint balance) {
        return balances[_owner];
    }

}

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based oncode by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is BasicToken, ERC20 {

    mapping (address => mapping (address => uint)) public allowed;

    uint public constant MAX_UINT = 2**256 - 1;

    /**
    * @dev Transfer tokens from one address to another
    * @param _from address The address which you want to send tokens from
    * @param _to address The address which you want to transfer to
    * @param _value uint the amount of tokens to be transferred
    */
    function transferFrom(address _from, address _to, uint _value) public onlyPayloadSize(3 * 32) {
        var _allowance = allowed[_from][msg.sender];

        // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
        // if (_value > _allowance) throw;

        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        if (_allowance < MAX_UINT) {
            allowed[_from][msg.sender] = _allowance.sub(_value);
        }
        uint sendAmount = _value.sub(fee);
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(_from, owner, fee);
        }
        Transfer(_from, _to, sendAmount);
    }

    /**
    * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
    * @param _spender The address which will spend the funds.
    * @param _value The amount of tokens to be spent.
    */
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {

        // To change the approve amount you first have to reduce the addresses`
        //  allowance to zero by calling `approve(_spender, 0)` if it is not
        //  already 0 to mitigate the race condition described here:
        //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
        require(!((_value != 0) && (allowed[msg.sender][_spender] != 0)));

        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
    }

    /**
    * @dev Function to check the amount of tokens than an owner allowed to a spender.
    * @param _owner address The address which owns the funds.
    * @param _spender address The address which will spend the funds.
    * @return A uint specifying the amount of tokens still available for the spender.
    */
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        return allowed[_owner][_spender];
    }

}


/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused public {
    paused = true;
    Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused public {
    paused = false;
    Unpause();
  }
}

contract BlackList is Ownable, BasicToken {

    /////// Getters to allow the same blacklist to be used also by other contracts (including upgraded Tether) ///////
    function getBlackListStatus(address _maker) external constant returns (bool) {
        return isBlackListed[_maker];
    }

    function getOwner() external constant returns (address) {
        return owner;
    }

    mapping (address => bool) public isBlackListed;
    
    function addBlackList (address _evilUser) public onlyOwner {
        isBlackListed[_evilUser] = true;
        AddedBlackList(_evilUser);
    }

    function removeBlackList (address _clearedUser) public onlyOwner {
        isBlackListed[_clearedUser] = false;
        RemovedBlackList(_clearedUser);
    }

    function destroyBlackFunds (address _blackListedUser) public onlyOwner {
        require(isBlackListed[_blackListedUser]);
        uint dirtyFunds = balanceOf(_blackListedUser);
        balances[_blackListedUser] = 0;
        _totalSupply -= dirtyFunds;
        DestroyedBlackFunds(_blackListedUser, dirtyFunds);
    }

    event DestroyedBlackFunds(address _blackListedUser, uint _balance);

    event AddedBlackList(address _user);

    event RemovedBlackList(address _user);

}

contract UpgradedStandardToken is StandardToken{
    // those methods are called by the legacy contract
    // and they must ensure msg.sender to be the contract address
    function transferByLegacy(address from, address to, uint value) public;
    function transferFromByLegacy(address sender, address from, address spender, uint value) public;
    function approveByLegacy(address from, address spender, uint value) public;
}

contract TetherToken is Pausable, StandardToken, BlackList {

    string public name;
    string public symbol;
    uint public decimals;
    address public upgradedAddress;
    bool public deprecated;

    //  The contract can be initialized with a number of tokens
    //  All the tokens are deposited to the owner address
    //
    // @param _balance Initial supply of the contract
    // @param _name Token Name
    // @param _symbol Token symbol
    // @param _decimals Token decimals
    function TetherToken(uint _initialSupply, string _name, string _symbol, uint _decimals) public {
        _totalSupply = _initialSupply;
        name = _name;
        symbol = _symbol;
        decimals = _decimals;
        balances[owner] = _initialSupply;
        deprecated = false;
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transfer(address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[msg.sender]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferByLegacy(msg.sender, _to, _value);
        } else {
            return super.transfer(_to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transferFrom(address _from, address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[_from]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferFromByLegacy(msg.sender, _from, _to, _value);
        } else {
            return super.transferFrom(_from, _to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function balanceOf(address who) public constant returns (uint) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).balanceOf(who);
        } else {
            return super.balanceOf(who);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).approveByLegacy(msg.sender, _spender, _value);
        } else {
            return super.approve(_spender, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        if (deprecated) {
            return StandardToken(upgradedAddress).allowance(_owner, _spender);
        } else {
            return super.allowance(_owner, _spender);
        }
    }

    // deprecate current contract in favour of a new one
    function deprecate(address _upgradedAddress) public onlyOwner {
        deprecated = true;
        upgradedAddress = _upgradedAddress;
        Deprecate(_upgradedAddress);
    }

    // deprecate current contract if favour of a new one
    function totalSupply() public constant returns (uint) {
        if (deprecated) {
            return StandardToken(upgradedAddress).totalSupply();
        } else {
            return _totalSupply;
        }
    }

    // Issue a new amount of tokens
    // these tokens are deposited into the owner address
    //
    // @param _amount Number of tokens to be issued
    function issue(uint amount) public onlyOwner {
        require(_totalSupply + amount > _totalSupply);
        require(balances[owner] + amount > balances[owner]);

        balances[owner] += amount;
        _totalSupply += amount;
        Issue(amount);
    }

    // Redeem tokens.
    // These tokens are withdrawn from the owner address
    // if the balance must be enough to cover the redeem
    // or the call will fail.
    // @param _amount Number of tokens to be issued
    function redeem(uint amount) public onlyOwner {
        require(_totalSupply >= amount);
        require(balances[owner] >= amount);

        _totalSupply -= amount;
        balances[owner] -= amount;
        Redeem(amount);
    }

    function setParams(uint newBasisPoints, uint newMaxFee) public onlyOwner {
        // Ensure transparency by hardcoding limit beyond which fees can never be added
        require(newBasisPoints < 20);
        require(newMaxFee < 50);

        basisPointsRate = newBasisPoints;
        maximumFee = newMaxFee.mul(10**decimals);

        Params(basisPointsRate, maximumFee);
    }

    // Called when new token are issued
    event Issue(uint amount);

    // Called when tokens are redeemed
    event Redeem(uint amount);

    // Called when contract is deprecated
    event Deprecate(address newAddress);

    // Called if contract ever adds fees
    event Params(uint feeBasisPoints, uint maxFee);
}

# @version 0.2.12
# (c) Curve.Fi, 2021
# Math for crypto pools
#
# Unless otherwise agreed on, only contracts owned by Curve DAO or
# Swiss Stake GmbH are allowed to call this contract.

N_COINS: constant(int128) = 3  # <- change
A_MULTIPLIER: constant(uint256) = 10000

MIN_GAMMA: constant(uint256) = 10**10
MAX_GAMMA: constant(uint256) = 5 * 10**16

MIN_A: constant(uint256) = N_COINS**N_COINS * A_MULTIPLIER / 100
MAX_A: constant(uint256) = N_COINS**N_COINS * A_MULTIPLIER * 1000


@internal
@pure
def sort(A0: uint256[N_COINS]) -> uint256[N_COINS]:
    """
    Insertion sort from high to low
    """
    A: uint256[N_COINS] = A0
    for i in range(1, N_COINS):
        x: uint256 = A[i]
        cur: uint256 = i
        for j in range(N_COINS):
            y: uint256 = A[cur-1]
            if y > x:
                break
            A[cur] = y
            cur -= 1
            if cur == 0:
                break
        A[cur] = x
    return A


@internal
@view
def _geometric_mean(unsorted_x: uint256[N_COINS], sort: bool = True) -> uint256:
    """
    (x[0] * x[1] * ...) ** (1/N)
    """
    x: uint256[N_COINS] = unsorted_x
    if sort:
        x = self.sort(x)
    D: uint256 = x[0]
    diff: uint256 = 0
    for i in range(255):
        D_prev: uint256 = D
        tmp: uint256 = 10**18
        for _x in x:
            tmp = tmp * _x / D
        D = D * ((N_COINS - 1) * 10**18 + tmp) / (N_COINS * 10**18)
        if D > D_prev:
            diff = D - D_prev
        else:
            diff = D_prev - D
        if diff <= 1 or diff * 10**18 < D:
            return D
    raise "Did not converge"


@external
@view
def geometric_mean(unsorted_x: uint256[N_COINS], sort: bool = True) -> uint256:
    return self._geometric_mean(unsorted_x, sort)


@external
@view
def reduction_coefficient(x: uint256[N_COINS], fee_gamma: uint256) -> uint256:
    """
    fee_gamma / (fee_gamma + (1 - K))
    where
    K = prod(x) / (sum(x) / N)**N
    (all normalized to 1e18)
    """
    K: uint256 = 10**18
    S: uint256 = 0
    for x_i in x:
        S += x_i
    # Could be good to pre-sort x, but it is used only for dynamic fee,
    # so that is not so important
    for x_i in x:
        K = K * N_COINS * x_i / S
    if fee_gamma > 0:
        K = fee_gamma * 10**18 / (fee_gamma + 10**18 - K)
    return K


@external
@view
def newton_D(ANN: uint256, gamma: uint256, x_unsorted: uint256[N_COINS]) -> uint256:
    """
    Finding the invariant using Newton method.
    ANN is higher by the factor A_MULTIPLIER
    ANN is already A * N**N

    Currently uses 60k gas
    """
    # Safety checks
    assert ANN > MIN_A - 1 and ANN < MAX_A + 1  # dev: unsafe values A
    assert gamma > MIN_GAMMA - 1 and gamma < MAX_GAMMA + 1  # dev: unsafe values gamma

    # Initial value of invariant D is that for constant-product invariant
    x: uint256[N_COINS] = self.sort(x_unsorted)

    assert x[0] > 10**9 - 1 and x[0] < 10**15 * 10**18 + 1  # dev: unsafe values x[0]
    for i in range(1, N_COINS):
        frac: uint256 = x[i] * 10**18 / x[0]
        assert frac > 10**11-1  # dev: unsafe values x[i]

    D: uint256 = N_COINS * self._geometric_mean(x, False)
    S: uint256 = 0
    for x_i in x:
        S += x_i

    for i in range(255):
        D_prev: uint256 = D

        K0: uint256 = 10**18
        for _x in x:
            K0 = K0 * _x * N_COINS / D

        _g1k0: uint256 = gamma + 10**18
        if _g1k0 > K0:
            _g1k0 = _g1k0 - K0 + 1
        else:
            _g1k0 = K0 - _g1k0 + 1

        # D / (A * N**N) * _g1k0**2 / gamma**2
        mul1: uint256 = 10**18 * D / gamma * _g1k0 / gamma * _g1k0 * A_MULTIPLIER / ANN

        # 2*N*K0 / _g1k0
        mul2: uint256 = (2 * 10**18) * N_COINS * K0 / _g1k0

        neg_fprime: uint256 = (S + S * mul2 / 10**18) + mul1 * N_COINS / K0 - mul2 * D / 10**18

        # D -= f / fprime
        D_plus: uint256 = D * (neg_fprime + S) / neg_fprime
        D_minus: uint256 = D*D / neg_fprime
        if 10**18 > K0:
            D_minus += D * (mul1 / neg_fprime) / 10**18 * (10**18 - K0) / K0
        else:
            D_minus -= D * (mul1 / neg_fprime) / 10**18 * (K0 - 10**18) / K0

        if D_plus > D_minus:
            D = D_plus - D_minus
        else:
            D = (D_minus - D_plus) / 2

        diff: uint256 = 0
        if D > D_prev:
            diff = D - D_prev
        else:
            diff = D_prev - D
        if diff * 10**14 < max(10**16, D):  # Could reduce precision for gas efficiency here
            # Test that we are safe with the next newton_y
            for _x in x:
                frac: uint256 = _x * 10**18 / D
                assert (frac > 10**16 - 1) and (frac < 10**20 + 1)  # dev: unsafe values x[i]
            return D

    raise "Did not converge"


@external
@view
def newton_y(ANN: uint256, gamma: uint256, x: uint256[N_COINS], D: uint256, i: uint256) -> uint256:
    """
    Calculating x[i] given other balances x[0..N_COINS-1] and invariant D
    ANN = A * N**N
    """
    # Safety checks
    assert ANN > MIN_A - 1 and ANN < MAX_A + 1  # dev: unsafe values A
    assert gamma > MIN_GAMMA - 1 and gamma < MAX_GAMMA + 1  # dev: unsafe values gamma
    assert D > 10**17 - 1 and D < 10**15 * 10**18 + 1 # dev: unsafe values D
    for k in range(3):
        if k != i:
            frac: uint256 = x[k] * 10**18 / D
            assert (frac > 10**16 - 1) and (frac < 10**20 + 1)  # dev: unsafe values x[i]

    y: uint256 = D / N_COINS
    K0_i: uint256 = 10**18
    S_i: uint256 = 0

    x_sorted: uint256[N_COINS] = x
    x_sorted[i] = 0
    x_sorted = self.sort(x_sorted)  # From high to low

    convergence_limit: uint256 = max(max(x_sorted[0] / 10**14, D / 10**14), 100)
    for j in range(2, N_COINS+1):
        _x: uint256 = x_sorted[N_COINS-j]
        y = y * D / (_x * N_COINS)  # Small _x first
        S_i += _x
    for j in range(N_COINS-1):
        K0_i = K0_i * x_sorted[j] * N_COINS / D  # Large _x first

    for j in range(255):
        y_prev: uint256 = y

        K0: uint256 = K0_i * y * N_COINS / D
        S: uint256 = S_i + y

        _g1k0: uint256 = gamma + 10**18
        if _g1k0 > K0:
            _g1k0 = _g1k0 - K0 + 1
        else:
            _g1k0 = K0 - _g1k0 + 1

        # D / (A * N**N) * _g1k0**2 / gamma**2
        mul1: uint256 = 10**18 * D / gamma * _g1k0 / gamma * _g1k0 * A_MULTIPLIER / ANN

        # 2*K0 / _g1k0
        mul2: uint256 = 10**18 + (2 * 10**18) * K0 / _g1k0

        yfprime: uint256 = 10**18 * y + S * mul2 + mul1
        _dyfprime: uint256 = D * mul2
        if yfprime < _dyfprime:
            y = y_prev / 2
            continue
        else:
            yfprime -= _dyfprime
        fprime: uint256 = yfprime / y

        # y -= f / f_prime;  y = (y * fprime - f) / fprime
        # y = (yfprime + 10**18 * D - 10**18 * S) // fprime + mul1 // fprime * (10**18 - K0) // K0
        y_minus: uint256 = mul1 / fprime
        y_plus: uint256 = (yfprime + 10**18 * D) / fprime + y_minus * 10**18 / K0
        y_minus += 10**18 * S / fprime

        if y_plus < y_minus:
            y = y_prev / 2
        else:
            y = y_plus - y_minus

        diff: uint256 = 0
        if y > y_prev:
            diff = y - y_prev
        else:
            diff = y_prev - y
        if diff < max(convergence_limit, y / 10**14):
            frac: uint256 = y * 10**18 / D
            assert (frac > 10**16 - 1) and (frac < 10**20 + 1)  # dev: unsafe value for y
            return y

    raise "Did not converge"


@external
@view
def halfpow(power: uint256, precision: uint256) -> uint256:
    """
    1e18 * 0.5 ** (power/1e18)

    Inspired by: https://github.com/balancer-labs/balancer-core/blob/master/contracts/BNum.sol#L128
    """
    intpow: uint256 = power / 10**18
    otherpow: uint256 = power - intpow * 10**18
    if intpow > 59:
        return 0
    result: uint256 = 10**18 / (2**intpow)
    if otherpow == 0:
        return result

    term: uint256 = 10**18
    x: uint256 = 5 * 10**17
    S: uint256 = 10**18
    neg: bool = False

    for i in range(1, 256):
        K: uint256 = i * 10**18
        c: uint256 = K - 10**18
        if otherpow > c:
            c = otherpow - c
            neg = not neg
        else:
            c -= otherpow
        term = term * (c * x / 10**18) / K
        if neg:
            S -= term
        else:
            S += term
        if term < precision:
            return result * S / 10**18

    raise "Did not converge"


@external
@view
def sqrt_int(x: uint256) -> uint256:
    """
    Originating from: https://github.com/vyperlang/vyper/issues/1266
    """

    if x == 0:
        return 0

    z: uint256 = (x + 10**18) / 2
    y: uint256 = x

    for i in range(256):
        if z == y:
            return y
        y = z
        z = (x * 10**18 / z + z) / 2

    raise "Did not converge"

# @version 0.2.12
"""
@title Curve LP Token
@author Curve.Fi
@notice Base implementation for an LP token provided for
        supplying liquidity to `StableSwap`
@dev Follows the ERC-20 token standard as defined at
     https://eips.ethereum.org/EIPS/eip-20
"""

from vyper.interfaces import ERC20

implements: ERC20

interface Curve:
    def owner() -> address: view


event Transfer:
    _from: indexed(address)
    _to: indexed(address)
    _value: uint256

event Approval:
    _owner: indexed(address)
    _spender: indexed(address)
    _value: uint256

event SetName:
    old_name: String[64]
    old_symbol: String[32]
    name: String[64]
    symbol: String[32]
    owner: address
    time: uint256


name: public(String[64])
symbol: public(String[32])

balanceOf: public(HashMap[address, uint256])
allowance: public(HashMap[address, HashMap[address, uint256]])
totalSupply: public(uint256)

minter: public(address)


@external
def __init__(_name: String[64], _symbol: String[32]):
    self.name = _name
    self.symbol = _symbol
    self.minter = msg.sender
    log Transfer(ZERO_ADDRESS, msg.sender, 0)


@view
@external
def decimals() -> uint256:
    """
    @notice Get the number of decimals for this token
    @dev Implemented as a view method to reduce gas costs
    @return uint256 decimal places
    """
    return 18


@external
def transfer(_to : address, _value : uint256) -> bool:
    """
    @dev Transfer token for a specified address
    @param _to The address to transfer to.
    @param _value The amount to be transferred.
    """
    # NOTE: vyper does not allow underflows
    #       so the following subtraction would revert on insufficient balance
    self.balanceOf[msg.sender] -= _value
    self.balanceOf[_to] += _value

    log Transfer(msg.sender, _to, _value)
    return True


@external
def transferFrom(_from : address, _to : address, _value : uint256) -> bool:
    """
     @dev Transfer tokens from one address to another.
     @param _from address The address which you want to send tokens from
     @param _to address The address which you want to transfer to
     @param _value uint256 the amount of tokens to be transferred
    """
    self.balanceOf[_from] -= _value
    self.balanceOf[_to] += _value

    _allowance: uint256 = self.allowance[_from][msg.sender]
    if _allowance != MAX_UINT256:
        self.allowance[_from][msg.sender] = _allowance - _value

    log Transfer(_from, _to, _value)
    return True


@external
def approve(_spender : address, _value : uint256) -> bool:
    """
    @notice Approve the passed address to transfer the specified amount of
            tokens on behalf of msg.sender
    @dev Beware that changing an allowance via this method brings the risk
         that someone may use both the old and new allowance by unfortunate
         transaction ordering. This may be mitigated with the use of
         {increaseAllowance} and {decreaseAllowance}.
         https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    @param _spender The address which will transfer the funds
    @param _value The amount of tokens that may be transferred
    @return bool success
    """
    self.allowance[msg.sender][_spender] = _value

    log Approval(msg.sender, _spender, _value)
    return True


@external
def increaseAllowance(_spender: address, _added_value: uint256) -> bool:
    """
    @notice Increase the allowance granted to `_spender` by the caller
    @dev This is alternative to {approve} that can be used as a mitigation for
         the potential race condition
    @param _spender The address which will transfer the funds
    @param _added_value The amount of to increase the allowance
    @return bool success
    """
    allowance: uint256 = self.allowance[msg.sender][_spender] + _added_value
    self.allowance[msg.sender][_spender] = allowance

    log Approval(msg.sender, _spender, allowance)
    return True


@external
def decreaseAllowance(_spender: address, _subtracted_value: uint256) -> bool:
    """
    @notice Decrease the allowance granted to `_spender` by the caller
    @dev This is alternative to {approve} that can be used as a mitigation for
         the potential race condition
    @param _spender The address which will transfer the funds
    @param _subtracted_value The amount of to decrease the allowance
    @return bool success
    """
    allowance: uint256 = self.allowance[msg.sender][_spender] - _subtracted_value
    self.allowance[msg.sender][_spender] = allowance

    log Approval(msg.sender, _spender, allowance)
    return True


@external
def mint(_to: address, _value: uint256) -> bool:
    """
    @dev Mint an amount of the token and assigns it to an account.
         This encapsulates the modification of balances such that the
         proper events are emitted.
    @param _to The account that will receive the created tokens.
    @param _value The amount that will be created.
    """
    assert msg.sender == self.minter

    self.totalSupply += _value
    self.balanceOf[_to] += _value

    log Transfer(ZERO_ADDRESS, _to, _value)
    return True


@external
def mint_relative(_to: address, frac: uint256) -> uint256:
    """
    @dev Increases supply by factor of (1 + frac/1e18) and mints it for _to
    """
    assert msg.sender == self.minter

    supply: uint256 = self.totalSupply
    d_supply: uint256 = supply * frac / 10**18
    if d_supply > 0:
        self.totalSupply = supply + d_supply
        self.balanceOf[_to] += d_supply
        log Transfer(ZERO_ADDRESS, _to, d_supply)

    return d_supply


@external
def burnFrom(_to: address, _value: uint256) -> bool:
    """
    @dev Burn an amount of the token from a given account.
    @param _to The account whose tokens will be burned.
    @param _value The amount that will be burned.
    """
    assert msg.sender == self.minter

    self.totalSupply -= _value
    self.balanceOf[_to] -= _value

    log Transfer(_to, ZERO_ADDRESS, _value)
    return True


@external
def set_minter(_minter: address):
    assert msg.sender == self.minter
    self.minter = _minter


@external
def set_name(_name: String[64], _symbol: String[32]):
    assert Curve(self.minter).owner() == msg.sender
    old_name: String[64] = self.name
    old_symbol: String[32] = self.symbol
    self.name = _name
    self.symbol = _symbol

    log SetName(old_name, old_symbol, _name, _symbol, msg.sender, block.timestamp)